The present invention is directed to a thyristor having a low-reflection light-triggering structure and a method for manufacturing such a thyristor. The low-reflection light-triggering structure has a sequence of semiconductor layers of alternating conductivity types that comprise a p-emitter contacted by an electrode of an anode side, an n-base, a p-base and an n.sup.+ -layer for the recesses of an n-emitter contacted on a cathode side and of an auxiliary emitter or floating gate region, whereby the auxiliary emitter or floating gate region has no electrical contacting but has a low-reflection photon entry face.
A thyristor of this type is disclosed in the publication, "Novel Gate Structure for High Voltage Light-Triggered Thyristor", from the Japanese Journal of Applied Physics, Vol. 21 (1982) Supplement 21-1, pages 91 through 96. For reducing the reflection, a .lambda./4-layer of silicon oxide is provided. However, this has the disadvantage that the degree of reflection is highly dependent on the wavelength .lambda. and additional manufacturing process steps are required.